1. Field of the Invention
The present invention relates to a circularly polarized array antenna and, more particularly, to the circularly polarized array antenna that comprises a plurality of circularly polarized antennas.
2. Description of Related Art
In the field of high-frequency communication (e.g., artificial satellite communication), due to the effect of signals passing through the ionosphere, the circularly polarized array antenna is generally used as a medium to receive circularly polarized signals. Moreover, due to the possibility for existence of two orthogonal polarization signals, every single polarized signal can be used to carry data so that orthogonal polarized signals (such as right hand or left hand signals) can be used in a neighboring area.
As shown in FIG. 1, U.S. Pat. No. 4,543,579 entitled “Circular Polarization Antenna” discloses a traditional circular polarization antenna array antenna, comprising an input/output terminal 5 and traditional antenna elements 1-1 to 1-7. The traditional antenna elements 1-1 to 1-7 further couple to input/output terminal 5 via feeding lines 3-1 to 3-7 respectively. The traditional antenna elements 1-1 to 1-7 can form a set with two antenna elements respectively to receive circular polarization signals, further output the circular polarization signals to input/output terminal 5, and then via input/output terminal 5, output the polarization signals to an amplifier and demodulator (not shown in figure). Therefore, traditional circular polarization array antenna can function as the medium for transmitting/receiving circular polarization signals. However, there is still room for improvement to the traditional circular polarized array antenna. Moreover, the production process for traditional circular polarization antenna elements 1-1 to 1-7 is rather complex. With the spirit for researching and innovating, the inventors of the present invention aimed to improve the traditional circular polarization array antenna and finally invented the circular polarization array antenna according to the invention.